The use of preopened bags, typically sold in roll form, for packaging products is now well known. Such bags are disclosed and claimed in now expired U.S. Pat. No. 3,254,828 entitled Flexible Container Strips issued Jun. 7, 1966 to Hershey Lerner. The product disclosed in that patent has been sold commercially by Automated Packaging System, Inc. of Twinsburg, Ohio under the trademark Autobag for many years.
With a properly made Autobag product, the face of each bag is open from side bead seal to side bead seal while the back of the bag is connected seal to seal to the next succeeding bag in the chain. The connection is by a line of weakness in the form of perforations which permits facile separation of a loaded bag.
Where a bulky product is inserted in such a bag the face of the bag tends to distort and sag while the back of the bag being connected seal to seal does not. In order to produce an attractive and quality finished product, a number of steps have been taken to bring the face of the bag into registration in the back. Steps which have been used commercially include a bag deflator mechanism as disclosed in U.S. Pat. No. 3,861,113 issued Jan. 21, 1975 to H. Hampton Loughry entitled Packaging Apparatus and Method and a bag support as disclosed in U.S. Pat. No. 3,956,866 issued May 18, 1976 to Vincent Lattur.
While the Autobag product has enjoyed great commercial success, there are applications where the product is not fully satisfactory. For example where it is desirable to provide a recloseable bag Autobag products are not readily producible because the reclosure is typically transverse of the bag. Since Autobag products travel in a longitudinal direction during manufacture transverse reopenable capabilities are difficult to provide.
An example of an application where a recloseable feature is desired is the packaging of panty hose which typically must be "stuffed" into a bag. Another reason Autobag products are not fully satisfactory for panty hose is if one stuffs a bulky product into a bag of the Autobag type using, for example, a machine which is sold commercially under the designation H-100 such as the machine shown in U.S. Pat. No. 3,965,653 issued Jun. 29, 1976 to Bernard Lerner, the force of stuffing the product into the bag tends to separate the back of the bag from the succeeding bag along the line of weakness. Further, the opening through which the product has been stuffed is forced into a generally circular configuration which makes appropriate closing and sealing quite difficult.
The use of preformed bags interconnected in side by side relation have been proposed for loading relatively bulky products. According to this proposal each bag of the chain has a side to side through opening at its top for guiding the chain of bags along a mandrel to a conveyor section. A knife is positioned intermediate the conveyor section and the mandrel for opening the bags. Bags once opened are conveyed to a load station where sequentially and one at a time they are brought to rest in the load station. The open top is spread and a product is inserted. Once the product has been inserted the machine cycles to bring the next bag of the chain to the load station and the loaded bag is transported to a seal station.
The prior proposal had several drawbacks which included the intermittent motion required sealing and loading to occur concurrently. Accordingly the machine could cycle no faster than the time required to load a package or the time required to affect a seal, which ever was the slower. The mechanism for transporting the bags also served to be the mechanism which resisted applied bag loading forces and accordingly was a limiting factor on the amount of force that could be applied in loading a bag rather than the strength of the bag so limiting the force.
The proposed machine had a load station with a single size opening which limited the machine's use to bags of but a single size. Further no adequate provision was made for separating bags from the web reliably and consistently both in the form of partial separation prior to bag loading and complete separation after a bag was loaded.
Another problem with prior proposals involved the manner in which the loaded bags were sealed. Heated platens have been utilized by some proposals and hot air cartridges which blow hot air onto the loaded bags while they are being sealed have been utilized by others. With heated platens, Teflon.RTM. belts must be utilized throughout the sealing section to prevent the heated plastic bag from adhering to the belts. The seals produced by the platens have an unsealed portion at the top of the bag which must be trimmed and even after the trimming, a portion of unsealed plastic typically remains.
When loaded bags are not moving through the sealing section, the heat radiating from the platens or the hot air emitted by the hot air cartridges deteriorates the conveyor belts. If the machine is down for any reason, the platens or hot air cartridges must be turned off to prevent deterioration of the belts. When the machine is ready to run again, it must wait for the platens or the hot air cartridges to reach the proper temperature.